Automatic arrangement for a carburetor



Filed June 3, 1966 O t/24. 1 JEAN-PIERRE SOUBIS 3,348,324

AUTOMATIC ARRANGEMENT FOR A CARBURETOR 3 Sheets-Sheet 1 INVENTOR Fig.5

ATTORNEYS" JEAN-PIERRE SOUBIS 3,348,824 AUTOMATIC ARRANGEMENT FOR ACARBURETOR 3 Sheets-Sheet 2 Filed June 3, 1966 N YS.

,1967 JEAN-PIERRE SOUBIS 3, 8,8

AUTOMATIC ARRANGEMENT FOR A CARBURETOR Filed June 3, 1966 3 Sheets-Sheet3 Z INVENTOR' Jam Frre 504(5/3 Mafia {M 3 6 10% ATTORNEYS United StatesPatent Ofi 3,348,824 Patented Oct. 24, 1967 Free AUTOMATIC A 2 3 Claims.(Cl. 261-41) 10 ABSTRACT OF THE DISCLOSURE An automatic arrangement forthe carburetor of an internal combustion motor wherein the main inletpipe is provided with a main venturi. A rotating control elementcontrols the volume of gas admitted into such pipe. The carburetor isprovided with a jet having a cooperating needle. A rod support isrotated about its axis as a function of the rotation of the abovecontrol elements. A cam track has an internal bore through which the rodsupport passes and is adapted to allow the cam track to slide freelyalong the rod support. Means are provided for driving said cam track inrotation by the rod support and means are provided controlling thesliding of the cam track as a function of the depression prevailing inthe main inlet pipe downstream from the rotating control element. Afeeler cooperating with the needle is applied against the cam track byelastic means. An auxiliary feed pipe is provided for admitting air anda channel extends into such auxiliary feed pipe for feeding motor fuelto the air admitted in the auxiliary pipe. Means are provided forcontrolling the motor fuel feeding the auxiliary pipe operating inresponse to the depression prevailing in the main inlet pipe at thelevel of the neck of the main venturi.

This invention relates to an automatic arrangement for a carburetorassuring an exact automatic regulation of the richness of the motor fuelfor feeding the motor in accordance with the operating conditionsthereof.

Generally, combustion motors with exterior carburetion comprise anadmission pipe for the motor fluid into one or more cylinders. With thisadmission pipe there is associated a choke or venturi diminishinglocally the crosssection of the pipe and a valve or butterfly valvecontrolling the flow of working fluid admitted into one or morecylinders, that is to say the rate of feed to the latter.

The operating fluid entering into a combustion chamber through the inletpipe is a carbureted mixture obtained by feeding the pipe with air andsecuring a pulverization or emulsion of the liquid fuel, either in suchpipe itself, at the level of the choke neck, by means of an appropriatecarburetor arrangement, or in a separate auxiliary pipe, called asecondary or carburetion pipe, which opens into the inlet pipedownstream of the butterfly valve associated therewith. 0

There are also feed processes that can be qualified as heterogeneous, inopposition to the usual feed process, indicated above, according towhich the motor is fed with a homogeneous carbureted fluid. In theseheterogeneous feed processes the combustion chamber is fed by two 5distinct flows of different richness.

For example, in accordance with such a heterogeneous feed described inPatent 3,087,480 granted Apr. 30, 1963, to J. Baudry, the inlet pipefeeds the combustion chamber with non-carbonated air and a richcarbureted mixture is introduced simultaneously into such chamberthrough a secondary separate pipe which, this time, does not dischargeinto the preceding, but directly into the combustion chamber through anorifice distinct from that of the inlet pipe for air. These two orificesare uncovered by the same inlet valve during the suction phase of themotor and the end of the secondary pipe is oriented towards theelectrodes of the sparkplug.

Whatever may be the feed process chosen it is necessary to adapt therichness of the admitted mixture to the various conditions for theoperation of the motor.

The arrangement according to the invention has for an object to securein an exact way such adaption by automatic regulation of the richness ofthe motor fuel of a carbureted mixture feeding the motor (whether ahomogeneous carburetion or a heterogeneous carburetion in the senseindicated above) as a function of the depression Ap prevailing in thecombustion chamber and of the opening angle at of the butterfly valvecontrolling the volume of gas admitted (rate of inlet).

A given value couple (Ap, or) defines, in fact, an operating point ofthe motor, since the running speed N of the motor is then also fixed,Ap, or and N remaining connected by the same relation when the operatingconditions may vary.

The arrangement according to the invention regulates automatically thefuel content of the feed of an internal combustion motor which comprisesin the usual way a main inlet pipe and a rotating element such as abutterfly valve for controlling the rate of admission.

This arrangement is adapted to a carburetor provided with a jet and aneedle which penetrates into the jet for limiting the cross-section ofthe passage for the motor fuel across the same, with elastic means suchas a spring associated with said needle.

According to the invention one uses a rod fixed in rotation with theelement controlling the rate of admission, a cam track or cam with threedimensions having an internal bore for said rod with a cross-sectionallowing the sliding of the cam track along said rod, which is moreoveradapted to entrain in rotation the cam track when it is itself driven inrotation by the element controlling the rate of admission.

The cam track is associated with an arrangement controlling itsdisplacement along said rod as a function of the depression prevailingin the main pipe of the motor, downstream of the rotating elementcontrolling the rate of admission. The arrangement comprises also afeeler cooperating with said needle and applied against the cam track byelastic means associated with the needle.

The invention will be described below in greater detail referring tosome examples of construction not in any limiting sense, illustrated inthe drawings in which:

FIGURE 1 shows a top view with parts in cross-section of a carburetionarrangement according to the invention.

FIGURE l-a shows a cross section line aa of FIGURE 1 and a cylinder inthe case of a hetereogeneous feed of the motor.

FIGURE 2 is a cross-sectional View on a larger scale of the cam trackalong section line aa of FIGURE 1.

FIGURE 3 is a perspective view of one way of constructing the rod uponwhich the cam track slides.

FIGURE 4 is an elevational view with parts in section showing oneexample of a construction for controlling the longitudinal displacementsof the cam track.

FIGURE 5 is a schematic view showing a construction wherein the feeleris applied upon the profile of the cam track through the intermediary ofa lever.

FIGURE 6 is a cross-sectional view similar to FIGURE 1a illustrating amodification.

FIGURE 7 is a perspective view of a device for consectional view takenalong trolling the simultaneous rotation of the butterfly valve and ofthe cam track.

In the embodiment shown by way of example in FIG- URE 1a, the inventionis used for the heterogeneous feed of a motor according to the processdescribed in the above cited patent, without having any limitingcharacter. A combustion chamber 1 is shown only partially having apiston 2, a cylinder 3 and a spark plug 4.

The inlet valve 5 is of the type described in application Ser. No.435,427 filed Feb. 26, 1965, now Patent No. 3,331,361.

According to the process described in the above cited patent there issecured a heterogeneous feed of the combustion chamber 1 by admittinginto said chamber through two separated conduits 32 and 38, twodifferent fluids across two distinct orifices respectively, 12 and 34uncovered by the same valve head 35 in the open position of the inletvalve 5.

One ofthe fluids admitted through the inlet conduit 32 is preferablynoncarbureted air while that in the other conduit isa rich carburetedmixture.

The end portion 36 of the conduit 38 has such an orientation that it isdirected towards the electrodes 37 of the spark plug in the openposition of the inlet valve 5.

In this way one can maintain up to the moment of firing a suflicientlocal richness in the neighborhood of the electrodes in order to permitthe combustion of the aggregate poor heterogeneous mixture admitted intothe chamber 1 during the suction phase. The inlet conduit 32 is fed byair through the main pipe 6 in which such air arrives at the end 7 afterhaving traversed a filter not shown.

The pipe 6 comprises a choke 8 reducing the cross section of the pipelocally and a main butterfly valve 9 which regulates the flow of airadmitted into the chamber 1, this main butterfly valve. rotating aboutits axis 10.

Downstream fromthe main butterfly valve 9 controlling the rate ofsupplying the cylinder, the air admitted traverses the chamber 11 beforeflowing through the conduit 32 and the orifice 12 into the chamber 1when the admission valve 5 is in open position.

The rich carbureted mixture which, upon its admission into the chamber 1is, according to the process described in the above cited patentproduced in the secondary pipe 13 and directed towards the electrodes 37of the spark plug.

This pipe 13 is associated with a carburetor arrangement having an airadmission conduit 14 comprising a secondary choke 15 in the neck ofwhich is secured in the usual way a pulverization or emulsion of theliquid motor fuel. This latter is contained in the container 20 comingthrough the conduit 21 whose orifice 24 is controlled by the needle 23fixed to the float 22, thereby maintaining the level of motor fuel inthe container 20 constant.

The container 20 feeds a liquid motor fuel across the calibrated jetorifice 25 to the chamber 26 adjacent the container 20, the tube 27having one end discharging at 28 into the neck of the secondary chokewhere it produces the pulverization or emulsion of the motor fuel intothe air admitted through 14.

The flow of carbureted mixture (air+motor fuel) thus produced iscontrolled by the secondary butterfly valve 16 upon the axis 17, thecontrol of this butterfly valve being synchronized with that of the mainbutterfly valve 9 by the usual system of rods and links connecting theaxes of these two butterfly valves.

The pipe 13 into which the carbureted mixture flows is prolonged by apipe 33 discharging through the orifice 41 into the bore of the guide 39of the valve rod.

This rod has an axial conduit 38 communicating with an end conduit 36located upon the internal face of the valve head 35 and making an elbowwith the preceding. The axial conduit discharges into the bore of thevalve guide 39 through an orifice 40.

The respective locations of the orifices 40 and 41 are chosen so thatthese orifices face one another in the opening position of the valve 5(suction phase), thus then discharge ed when theinlet valve is in closedposition as in FIGURE la when the orifices 40 and 41 are no longer faceto face.

The element 42 fixed upon the guide 39 of the valve and being in contactwith the flat 43 provided upon the rod of such valve is designed toprevent any rotation thereof which would have the effect of modifyingthe orientation of the conduit 36.

The conduit 29 establishing a communication between the upper portion ofthe chamber 26 and the choke neck 8 across the calibrated orifice 30 isdesigned, by creating in the chamber 26 downstream from the jet 25 adepression varying as that prevailing in the choke neck, to make theflow of fluid pulverized or emulsionated at 28 vary as the flow of airadmitted into the motor by the main pipe 6.

Another calibrated orifice 31, establishing a communication between thechamber 26 and the pipe 14 makes the flow of fuel to vary only veryslightly at 28 when the main butterfly valve 9 is closed progressively,without the orientation of the butterfly valve 16 being modified inspite of the increase of flow in the channel 13 which is produced thenas a consequence of the higher depression in the combustion chamber.This system being adapted to start to progressively close the butterflyvalve 16 in synchronism with the main valve 9, exclusively toward theend of the closing of this main valve, while the butterfly valve 16 isnot driven in rotation with said main valve 9 for more open positions ofthe latter.

The axis 10 of the main butterfly valve 9 controlling the rate of feedto the cylinder is fixed upon the rod 44, as

seen in FIGURE 1, whereby rod 44 is rotated by butterfly valve 9 whenthe orientation of the latter is modified.

This rod 44 traverses a cam track or 3-dimensional cam 45 through a bore46 provided in the cam track, as shown in FIGURE 2.

A pin 44a fixed to the rod 44 is guided by a slot 46a located in the thebore 46 parallel to the axis of the rod and assures the rotation of thecam track about the axis of such rod when the butterfly valve 9 rotatesand allows the cam track to be displaced freely parallel to its axis.This rotation may also be obtained by giving to the rod 44 and the bore46 appropriate complementary cross sections, the rod 44 having forexample, the form shown in FIGURE 3, if the cross-section of the bore 46is that of FIGURE 2.

In such example, meansformed by a depression capsule 47, whosecompartment 48 communicates by the pipe 49 with the space 11, controlsas a function of the depression prevaling in such space thedisplacements of the cam track parallel to the axis of the rod 44.

The cam track is fixed to the flexible membrane 5t) of the capsule 47upon which the depression prevailing in the chamber 11 acts and which issubjected moreover to the action of one or more antagonistic springs 51.

The depression to which the capsule 47 is subjected is that prevailingdownstream of the main butterfly valve 9 in the flow of fluid traversingthrough the main channel 6.

In place of a depression capsule it would be possible to use any otherarrangement fulfilling the same function, for example the arrangementshown in partial cross-section in FIGURE 4 where the piston 18 is fixedto the cam track 45 and slides in the cylinder 19 whose bottom isconnected to the main inlet pipe 6 of the motor downstream ofthe mainbutterfly valve 9 as the depression capsule of FIGURE 1.

A needle 56 sliding in an orifice 52 provided at the the chamber 1 alongthe base of the container 20 of the carburetor has a first endcomprising a feeler 53 which is maintained in contact with the lateralsurface of the cam track 45 by an elastic system formed by a spring 54compressed between an abutment upon the rod 56 and the wall of the tank20. The other end 55 of the needle 56 is tapered and cooperates with thecarbureted jet orifice 25 of the carburetor controlling the crosssection of such passage.

It is seen that if the cam track does not have a cylindrical form ofrevolution about its rod support 44 the cross section of the passage ofthe jet 25 and consequently the flow of pulverized or emulsated motorfluid at 28, will vary with the displacements of the needle 56 when themain butterfly valve 9 may turn, thus modifying the rate of feed to thecylinder and, when the cam track 45 should be displaced along the rod44, as a function of the variations of the depression in the chamber 11.

In order to obtain according to the invention the exact automaticregulation of the richness of the carbureted mixture feeding the motoras a function of its load and its operation, it would sufiice thereforeto give to the cam track the form corresponding to the optimal fiow ofmotor fuel for each value of the orientation angle a of the mainbutterfly valve 9 and each value of the depres sion Ap, each of saidcouples of values define, as has already been indicated, a point ofoperation of the motor since these values and the running speed N of themotor are interrelated.

This may be obtained by determining experimentally the position of theneedle 56 giving the optimal richness for each couple oz, Ap defining anoperational point of the motor and by noting the distance from the axisof the rod 44 of the feeler 53 for such position.

The form of the cam track 45 will be deduced from the measurements thusmade.

In practice, in order to obtain the maximum of exactitude it would besuitable that the total travel of the needle 56 corresponds to avariation of cross section as slight as possible of the calibratedorifice 25 (this total travel being limited by the slope which shouldnot be exceeded upon the cam track and the bulkiness of the device whichshould not be excessive). It is therefore advantageous to obtain apreregulation of the flow of motor fuel at 28, which in the particularcase of a heterogeneous feed would correspond to an average richness ofthe heterogeneous mixture admitted into the chamber 1 close to the basicrichness of a single homogeneous feed.

This rough preliminary operation can be obtained through the systemformed by the chamber 26 communicating at its top through the conduit 29with the neck of the choke 8, which as has been seen, by imposingdownstream of the jet 25 a depression as a function of the air flow intothe pipe 6, brings the flow of motor fuel under the control of the flowof air.

As shown in FIGURE 5 it would be possible to inter pose between theneedle 56 and the feeler 53- a demultiplying lever 57 pivoted about afixed point 58.

It is understood that the arrangement according to the invention ofwhich a form of construction has been described in its application to aheterogeneous feed process for motors with exterior carburetion shouldnot be limited to such a single application.

It can also be used in the case of a homogeneous feed with a singlecarbureted mixture, the arrangement being then controlled simultaneouslyby the rotation of a butterfiy valve controlling the rate of feed to oneor more cylinders and the variations of the depression in these latter.

In order to obtain a homogeneous feed with the arrangement according toFIGURE let it is sutficient to replace the inlet valve 5 by a valve 5'of the usual type as shown in FIGURE 6-, eliminate pipe 33 and establisha communication 59 between pipes 6 and 13, for example, an orifice atthe base of pipe 13 in order to permit the two flows to mix beforeentering into the combustion chamber 1. Such an arrangement according tothe inven- 6 tion adapted to a homogeneous feed is shown in FIG- URE 6.

In the case of a homogeneous feed it should evidently be possible toeliminate completely the passage 13 and to retain only the main pipe 6by causing the tube 27 of the carburetor to discharge into the neck ofthe main choke 8.

Nevertheless, in general, it may be preferred for a homogeneous feed toretain the assembly of the two pipes 6 and 13 from the arrangement ofFIGURE 1a by adapting them to a homogeneous feed as illustrated in FIG-URE 6 By retaining a main pipe 6 for a homogeneous carburetion which isonly a vehicle for the air it is possible to separate the functions forcarburetion and for supply, the carburetion being efiected in the pipe13 distinct from the main pipe 6 assuring the supply function.Consequently, there is for the main pipe 6 neither a limitation of thecross-section at the level of the choke 8, since there is nopulverization of the motor fuel in such pipe, nor any limitation oflength or of volume between such choke and the inlet orifice into thecombustion chamber since said pipe is not a medium for the motor fuelcapable of condensing in such portion.

Under these conditions one can give to the main pipe 6 dimensions betteradapted to secure an optimum feed of the combustion chamber in the rangeof operation provided for the motor, using the dynamic oversupply effectcalled the Kadenacy effect, observed in pulsating flows. The flow of airin the main inlet pipe is in fact in a vibratory state because of thealternating periods of opening and closing the inlet valve.

Consequently, by giving appropriate dimensions to the main pipe 6 andthe chamber 11, it is possible to obtain that for a given speed ofrotation of the motor, chosen in the scale of use, the opening of theinlet valve coincides with the existence of an overpressure at the levelof the inlet orifice for the fluid in a vibratory state in the main pipe6. There is thus obtained an excellent feed for the combustion chamberin the neighborhood of the considered speed and the feed is optimum forsuch operation (Kadenacy effect).

In the arrangement according to the invention adapted to a homogeneousfeed which is represented in FIGURE 6 the conduit 29 connecting the topof the chamber 26 of the carburetor with the neck of the choke 8 willpermit, as with the arrangement of FIGURE 1a, controlling the flow ofmotor fuel at 28' as a function of the air in the main pipe 6.

The calibrated orifice 31 provided in the construction of FIGURE 6 wouldhave the effect already indicated above with respect to the arrangementshown in FIGURE 10:.

The butterfly valve 9 controlling the admission may be either directlyfixed on the rod 44 supporting the cam track (FIGS. 1 and 1a) or coupledthereto through a lever and connecting rod system, as shown in FIGURE 7.

I claim:

1. In an automatic arrangement for the carburetor of an internalcombustion motor, comprising a main inlet pipe provided with a mainventuri, a rotating control element for controlling the volume of gasadmitted into said pipe, said carburetor being provided with a jet, aneedle cooperating with said jet, elastic means associated with saidneedle, a rod support, means for rotating said rod support about itsaxis as a function of the rotation of said control element, a cam trackof nonuniform cross section in the axial direction having an internalbore through which said rod support passes, and adapted to allow saidcam track to slide freely along said rod support, means for driving inrotation said cam track by said rod support, means controlling thesliding of said cam track as a function of the depression prevailing insaid main inlet pipe, downstream from said rotating control element anda feeler cooperating with said needle applied against said cam track bysaid elastic means, the

provision of an auxiliary feed pipe, means for admitting air into saidpipe, a channel extending into said auxiliary feed pipe for feedingmotor fuel to the air admitted in said auxiliary pipe and control meansfor the flow of motor fuel feeding said auxiliary pipe, operating inresponse to the depression prevailing in said main inlet pipe at thelevel of the neck of said main venturi.

2. An arrangement according to claim 1, wherein said control means forthe flow of motor fuel feeding said auxiliary pipe comprises anauxiliary chamber above said channel feeding motor fuel to saidauxiliary pipe and a conduit connecting the upper portion ofsaid chamberwith said main inlet pipe at the level of the neck of said main venturi.

3. An arrangement according to claim 2, wherein said auxiliary feed pipeincludes an auxiliary butterfly valve for regulating the flowtherethrough, an auxiliary venturi located upstream from said auxiliarybutterfly valve and a calibrated orifice communicating with saidauxiliary feed pipe, at the level of the neck of said auxiliary venturiand with the upper portion of said auxiliary chamber.

References Cited UNITED STATES PATENTS HARRY B. THORNTON, PrimaryExaminer. TIM R. MILES, Examiner.

1. IN AN AUTOMATIC ARRANGEMENT FOR THE CARBURETOR OF AN INTERNALCOMBUSTION MOTOR, COMPRISING A MAIN INLET PIPE PROVIDED WITH A MAINVENTURI, A ROTATING CONTROL ELEMENT FOR CONTROLLING THE VOLUME OF GASADMITTED INTO SAID PIPE, SAID CARBURETOR BEING PROVIDED WITH A JET, ANEEDLE COOPERATING WITH SAID JET, ELASTIC MEANS ASSOCIATED WITH SAIDNEEDLE, A ROD SUPPORT, MEANS FOR ROTATING SAID ROD SUPPORT ABOUT ITSAXIS AS A FUNCTION OF THE ROTATION OF SAID CONTROL ELEMENT, A CAM TRACKOF NONUNIFORM CROSS SECTION IN THE AXIAL DIRECTION HAVING AN INTERNALBORE THROUGH WHICH SAID ROD SUPPORT PASSES, AND ADAPTED TO ALLOW SAIDCAM TRACK TO SLIDE FREELY ALONG SAID ROD SUPPORT, MEANS FOR DRIVING INROTATION SAID CAM TRACK BY SAID ROD SUPPORT, MEANS CONTROLLING THESLIDING OF SAID CAM TRACK AS A FUNCTION OF THE DEPRESSION PREVAILING INSAID MAIN INLET PIPE, DOWNSTREAM FROM SAID ROTATING CONTROL ELEMENT ANDA FEELER COOPERATING WITH SAID NEEDLE APPLIED AGAINST SAID CAM TRACK BYSAID ELASTIC MEANS, THE